governments control the courts; they exempt themselves from liability for things all the time. for instance: try suing the cops in the US because they didn't do enough to protect you.
Wrong, this happens all the time. For example, municipalities pay out all the time to the Westboro Baptist Church when local police are unable to defend them from the people they are intentionally enraging. (This is how WBC makes their money.)
That means that the WBC is the greatest troll of our time. They literally have nothing on 4chan.
Most constitutions in free countries establish some kind of system for checks and balances of power.